1. Field of the Invention
This invention relates to a copying apparatus in which two- or three-dimensional originals such as individual sheets or thick books are selectively driven over an illumination slit aperture.
2. Description of the Prior Art
In the copying apparatus of the described type, the slit aperture is projected, for example, on a drum carrying photosensitive paper thereon. The speed of rotation of the drum is made equal to the speed at which the originals are moved over the slit aperture. The images of the originals guided over the slit aperture are successively exposed onto the photosensitive paper on the drum. Thereafter, the photosensitive paper can be developed in a subsequent developing device in a known manner.
Such a copying apparatus has an advantage that both individual sheets and desired book pages can be copied. However, the operation of such apparatus is troublesome because the original is usually placed on a glass plate which is movable over the slit aperture, which glass plate must be covered in order not to dazzle the user. Accordingly, to position the original, a cover or a flap cover must first be opened so that the original can be placed on the glass plate, whereafter the cover or the flap cover must be shut again. The same procedures are required to remove the original. In addition, the original must be placed within a predetermined field on the glass plate in accordance with its size, so that copying with such apparatus is troublesome and time-consuming.
There is also known a device in which the originals, when they are individual sheets, are directly inserted into a guide groove in the device and gripped by transport rolls so as to move through the device. In this case, one can successively introduce individual sheets as originals into the device, thereby enabling quick and simple copying to take place. However, this device does not permit copies of books to be obtained.
Accordingly, it has already been proposed that for copies of individual sheets, two sets of transport rolls be used to guide the sheets over the illumination slit aperture and that for copies of desired book pages, the upper rolls of the transport mechanism for individual sheets be detachably arranged and a glass plate with a book resting thereon be guided by utilizing the remaining lower transport rolls of the transport mechanism. The remaining lower transport rolls are frictionally engageable with the glass plate to ensure the automatic transport thereof.
This arrangement has the disadvantages that, to obtain copies of books, part of the apparatus must be detached to change the construction thereof and, moreover, the detached apparatus part must be placed somewhere else during copying.